<!DOCTYPE html>
<html>

	<head>
		<meta charset="UTF-8">
		<title>argument对象</title>
	</head>

	<body>
		<div id="div1" style="width:200px;background: red;height: 200px;"></div>
		<script>
			//传入2个参数，获取属性值，传入3个参数 设置属性值
			function css() {
				if(arguments.length == 2) {
					return arguments[0].style[arguments[1]];
				} else if(arguments.length == 3) {
					//div1.style.background=green
					arguments[0].style[arguments[1]] = arguments[2];
					//div1.style[background]=green
				} else {
					alert("no")
				}
			}
			//页面加载时执行
			window.onload = function() {
				var div1 = document.getElementById("div1");
				//获取div1元素的width的值
				alert(css(div1, "width"));
				//设置 div1元素的background属性为green
				css(div1, "background", "green");
			}
			
		</script>

	</body>

</html>